Data storage systems (DSSes) are integrated systems that allow persistent data storage to be presented to remote host devices in an efficient manner. A host may transmit data storage commands to the DSS for processing. A DSS may be configured as one or more storage processors attached to underlying persistent storage, each storage processor being configured to process data storage commands.
Data of a DSS may be organized into logical disks. These logical disks may be provisioned with backing store. In some systems, specialized tracking data structures are used to keep track of discrete extents of backing store underlying the portion of a logical disk to which an Input/Output (I/O) command is directed. Because only a fixed number of tracking data structures may be provisioned within the DSS for use in processing I/O commands, the DSS may enforce a maximum permitted size of an I/O.